Method of regenerating sulphurous acid and the heat of the waste gas from cellulose boilers



NQV: 18, H. CLEMM METHOD OF REGENERATING SULPHUROUS ACID AND THE HEAT OF THE WASTE GAS FROM CELLULOSE BOILERS Filed Nov. 27, 1922 5 gas from the boiler by means Patented Nov. 18, 1924.

nrrsn s'r' TEs PATENT] OFFICE.

HANS CLEMM, OF MANNHEIM-WALDHOF, GERMANY, ASSIGNOR TO ZELLSTOFFFABRIK WALDHOF, OF MANNHEIM-WALDHOF, GERMANY.

METHOD OF REGENERATING SULPHUROUS ACID AND THE HEAT or THE wes'rn GAS- FROM CELLULOSE BOILERS.

Application filed November 27, 1922. Serial No. 603,567.

To all whom it may concern:

Be it known that l, HANS OLE-MM, a citizen of Germany. residing at Mannh eim- Waldhof, in the State of Baden, Germany.

have invented certain new and usefuh Improvements in Methods of Regenerating Sulphurous Acid and the Heat of the \Vaste Gas from Cellulose Boilers; and I do hereby declare the following to be a full, clear,

and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

. My invention relates to improvements in the method of and system for regenerating sulphurous acid and the heat of the waste .gas from cellulose boilers. Inthe manufacture of sulfit cellulose various'methods have been designed to regenerate the sulphurous acid remaining after boiling within the boilers and the heat of the waste gas. Ordinarily for removing the said gas from the boiler only the pressure within the boiler is made use of. For example. where it is intended touse the waste gas for supplying the sulphurous acid (S0 to a fresh charge of boiling liquor the discharge from the boiler is connected by a pipe including cooling means with the receptacle containing the fresh liquor so that when opening the discharge valve the gasfrom the boiler, which is under a pressure of several atmospheres,

flows into the said receptacle after being cooled, whereupon it is absorbed .by the liquor. Where the fresh liquor. is contained within a closed receptacle the gas can be .transmitted into the same without cooling,

so that also the heat is regenerated.

However, in both cases the regeneration of the sulphurous acid and the heat is incomplete, the gas chamber of the boiler remaining filled with gas after discharging the same in the manner indicated, especially as the pressure within the boiler does not i fall off to atmospheric pressure, by reason of the high levelof the fresh liquor and the pressure produced in some cases within the receptacle containing the fresh liquor.

It has also been proposed to withdraw the of a suction pump and to pass the same through condensers, absorptionapparatus, and the like.

whether hot or cold can be forced into ting the i But in such cases also the regeneration of the sulphurous acid is incomplete, because the suction pump connected to the system is just suflic'ent to overcome the resistances withinthe system, and it is not enabled to roduce a vacuum within the gas chamber of the boiler. 'Furthermore it is impossible by this method directly to transmit the sulphurous acid of the waste gas to the fresh liquor, or directly to pass the same into the fresh liquor for regenerating the heat thereof. By withdrawing the gas by suction the proportion of sulphurous acid within the fresh liquor would not be raised but reduced.

The object of the improvements is to pro vide a method and a system whereby the sulphurous acid is completely regenerated and in addition the heat of the waste gas is made use of. With this object in view the gas is directly withdrawn from the boiler by means of a compressor and passed under pressure for further use-to any desired'apparatus. By the suction of the compressor the pressure within the boiler is reduced below atmospheric pressure, so that a vacuum is produced within the boiler and above the liquor. Thereby not only the sulphurous acid contained in the gas chamber is withdrawn, but, by reason of the vacuum, also the major part-of the sulphurous acid contained 'in the liquor is withdrawn and re generated. By conveying the waste gas to the place of use under pressure, the ggs t e fresh liquor, irrespective of the level thereof, which liquoris enclosed for example within a closed receptacle.

In order that my invention be more clearly understood a system suitable for putmethod into effect has been shown by way of example in the accompanying drawing showing the system in a diagrammatical way.

-' In the example shown in the drawing the waste gas is withdrawn from the boiler, (a atthetop thereof through a pipe I) and by means of a compressor a. By the said compressor the gas is conveyed under pressure through a pipe 6 and into a receptacle d containing the fresh liquor, the gas being taken up by the fresh liquor. In lieu of the receptacle (Z other apparatus such as boilers, condensing apparatus, or absorbing apparatus may be provided.

claim:

1. The herein-described method of regenerating sulphurous acid and heat from waste gas contained in cellulose boilers which consists in withdrawingthe mixture of vapor and gas therefrom to a degree to produce a partial vacuum in the boiler, and in conveying the vapor and gas to a place of use, whereby not only the sulphurous acid contained inthe gas chamber of the boiler is withdrawn but also the major part of the sulphurous acid contained in the liquor in the boiler is withdrawn and-regenerated.

2. The herein-described method of regenerating sulphurous acid and heat from waste gas contained in cellulose boilers which consists in withdrawing the mixture of vapor and gas therefrom to a degree to produce a partial vacuum in the boiler, and in conveymg the vapor and gas to a place of use, whereby not only the sulphurous acid in the gaschamber of the boiler is withdrawn but also the major part of the sulphurous acid waste gas contained in cellulose boilers which consists in withdrawing the vapor and gas therefrom to a degree to produce a partial vacuum in the boiler and in conveying the vapor and gas under pressure to a closed chamber, this chamber containing fresh liquor, whereby not only the sulphurous acid in the gas chamber of the boiler is withdrawn, but also the major part of the sulphurous acid contained in the liquor in the boiler is withdrawn and regenerated.

In testimony whereof I hereunto aflix my signature in the presence of two witnesses.

DR. HANS OLEMM.

Witnessesz' C. C. L. B. WYLEs, H. SCHICKERT. 

